Spectroscopic tracking of molecular transport junctions generated by using click chemistry.
Spectroscopic tracking of molecular transport junctions generated by using click chemistry.
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DOI：
10.1002/anie.200806028
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发表时间：
2009
期刊：
影响因子：
--
通讯作者：
Mirkin CA
中科院分区：
文献类型：
--
作者：
Chen X;Braunschweig AB;Wiester MJ;Yeganeh S;Ratner MA;Mirkin CA
构建分子传输结(MTJ)的有效方法的发展继续挑战分子电子学领域。[1，2]目前MTJ制造的大部分工作主要依赖于分子导线(例如二硫醇分子)的异地合成，随后将分子插入到GAP器件中。与这种方法相关的问题是：1)由于这些分子的低稳定性和合成产率，在两端用硫醇合成长分子导线涉及到困难，2)连接电极的复杂性，因为这种分子导线有很强的聚集倾向。[4]此外，小的结尺寸(通常只有几个纳米宽)通常禁止使用常规的光谱工具来鉴定MTJ中的含量。因此，值得开发一种模块化的方法，用于原位合成分子导线以桥接纳米GaP[4，5]，从而允许对组装过程进行光谱跟踪。在这里，我们报道了一种新的方法，利用在线光刻(OWL)制备的纳米GaP中的炔叠氮“点击反应”来制备MTJ，同时使用表面增强拉曼散射(SERS)来表征缝隙中的组装过程。这种形成MTJ的策略以高产率进行，并且由于点击化学的可及官能团要求，是一种可用于形成由不同分子组分组成的MTJ的模块化方法。此外，这种方法非常适合于研究各种分子结构的传输特性，因为由炔基和叠氮基反应形成的三氮唑保留了电子传输所需的共轭。**CAM感谢NSF-NSEC的支持。CAM还感谢国防部提供的NSSEF奖学金。ABB对获得NIH博士后奖学金表示感谢。SY感谢ONR给予NDSEG奖学金。MAR承认来自NU MRSEC的资金。
The development of efficient methods for constructing molecular transport junctions (MTJs) with the capability to spectroscopically identify molecules assembled within the junctions continues to challenge the field of molecular electronics.[1, 2] Most of the current work in MTJ fabrication relies primarily on ex situ syntheses of molecular wires (eg dithiolated molecules) followed by subsequent insertion of the molecules into the gap devices.[3] The problems associated with this approach are: 1) the difficulty involved in synthesizing long molecular wires with thiols on both ends because of the low stability and synthetic yields of these molecules, and 2) complications in bridging the electrodes because of a strong tendency of such molecular wires to aggregate.[4] In addition, the small junction sizes (normally only several nanometers in width) often prohibit the use of routine spectroscopic tools to identify the contents within MTJs. Therefore, a modular method for in situ synthesis of molecular wires to bridge nanogaps [4, 5] that allows spectroscopic tracking of the assembly process merits development. Herein, we report a new method to fabricate MTJs using the alkyne-azide “click reaction” within nanogaps fabricated by On-Wire Lithography (OWL), while using surface enhanced Raman scattering (SERS) to characterize the assembly processes within the gaps. This strategy for forming MTJs proceeds in high yields, and, as a result of the accessible functional group requirements of click chemistry, is a modular approach that can be used to form MTJs comprised of different molecular components. Additionally, this approach is well suited for studying transport properties of various molecular architectures because the resulting triazole formed by reacting the alkyne and azide groups retains the conjugation required for the electronic transport.** CAM acknowledges support from the NSF-NSEC. CAM is also grateful for an NSSEF Fellowship from the Department of Defense. ABB is grateful for an NIH Postdoctoral Fellowship. SY is thankful to the ONR for an NDSEG fellowship. MAR acknowledges funding from the MRSEC at NU.